This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Bromus secalinus L. Sp. PI. 76. 1753.
Culms 1°-3° tall, erect, simple, smooth and glabrous. Sheaths usually shorter than the internodes, generally glabrous; ligule 1/2" long, erose; blades 2'-9' long, 1"-3" wide, smooth or rough, sometimes hairy; panicle 2's' in length, open, its branches ascending or drooping; spike-lets turgid, glabrous, erect or somewhat pendulous, 6-10-flowered; empty scales scabrous toward the apex, the first 3-nerved, acute, the second longer and broader, 7-nerved, obtuse; flowering scales 3"-4" long, broad, turgid, obtuse, rough toward the apex, the nerves obscure, awnless, or bearing a straight awn 4" long or less between the obtuse short teeth; palet about equalling the scale.
Bromus racemosus L. Sp. PL Ed. 2, 114. 1762. B. commutatus Schrad. Fl. Germ. 1: 353. 1806.
Culms 1°-3° tall, erect, simple, smooth and glabrous, or sparingly pubescent below the panicle. Sheaths shorter than the internodes, glabrous or pubescent; ligule 1" long; blades 1'-9 long, 1/2'-4" wide, pubescent; panicle i'-io' in length, the branches erect or ascending, the lower sometimes 2 1/2' long; spikelets erect, 5-11-flowered; empty scales acute, the first 3-nerved, the second longer and broader, 5-9-nerved; flowering scales broad, 3 1/2"-4 1/2" long, obtuse, smooth and shining, the nerves prominent; awn straight, 3"-4" in length; palet considerably shorter than the scale.
In fields and waste places all over the United States and British America. Naturalized from Europe. Native also of Asia. June-Aug.
Bromus arvensis L. Sp. PI. 77. 1753.
Culms erect, 1°-3° tall, smooth and shining, glabrous except at or near the brown nodes. Sheaths shorter than the intemodes, softly and densely pubescent with short reflexed hairs; ligule scarious, 1/2"-l 1/2" long; blades erect or ascending, more or less hirsute on both surfaces, 3'-6' long, 2"-3" wide; panicle ample, 5'-9' long, its rough branches erect or ascending, rarely spreading, branching and spikelet-bearing above the middle, the longer 3'-6' long; spikelets, including the awns, 9"-12" long, lanceolate, somewhat shining, the scales membranous, scarious on the margins, minutely and sparsely appressed-pubescent toward the acute apex, papillose along the nerves, the first scale 3-nerved, the second 5-nerved; flowering scales broadest at the middle, 5-nerved, 3 1/2"-4" long, bearing an erect awn of about the same length.
Fields and waste places, New York to Michigan, Missouri and Florida. Locally adventive from Europe. Summer.